1. Field of the Invention
The present invention relates to an insertion device, and a rotating tubular member provided in (to) the insertion device. The insertion device includes an insertion section extending along a longitudinal axis, and the rotating tubular member which is rotatable relative to the insertion section in directions around the longitudinal axis.
2. Description of the Related Art
In an insertion device disclosed by one example in the specification of U.S. Patent Application Publication No. 2012/002981, a rotating tubular member rotatable relative to an insertion section in directions around a longitudinal axis is attached to the insertion section extending along the longitudinal axis. In this insertion device, a driving shaft which is a linear member extends through an inside of the insertion section along the longitudinal axis. A distal end of the driving shaft is connected to a driving unit. The driving unit includes a first gear to which the driving shaft is coupled, and a second gear which is toothed with the first gear. When a driving force is transmitted via the driving shaft, each of the first gear and the second gear rotates around a corresponding gear axis, and the driving unit is driven. The rotating tubular member is provided with an inner peripheral gear portion which is toothed with the second gear. When the driving unit is driven, the rotating tubular member rotates relative to the insertion section in one of the directions around the longitudinal axis.
The insertion portion includes a proximal side base member, and a distal side base member coupled to the distal direction side of the proximal side base member. A driving unit placement cavity in which the driving unit is disposed is defined by the proximal side base member and the distal side base member. The driving unit placement cavity is open with respect to an outside of the insertion section through an opening. A proximal side seal ring which is a proximal side ring member is provided on an outer peripheral portion of the proximal side base member. The proximal side seal ring is located to the proximal direction side of the opening of the driving unit placement cavity. A distal side seal ring which is a distal side ring member is provided on an outer peripheral portion of the distal side base member. The distal side seal ring is located to the distal direction side of the opening of the driving unit placement cavity. The proximal side seal ring maintains liquid-tightness between the outer peripheral portion of the proximal side base member and an inner peripheral portion of the rotating tubular member. The distal side seal ring maintains liquid-tightness between the outer peripheral portion of the distal side base member and the inner peripheral portion of the rotating tubular member. Therefore, the proximal side seal ring and the distal side seal ring prevent liquid inflow from the outside of the insertion section into the driving unit placement cavity, and prevent the driving unit from, for example, being damaged by a liquid.